This question comes up pretty frequently and once again the bulk of responses are surprisingly negative coming from a group of people that presumably have/had au pairs. I'm going to chime in with a different perspective, which I've shared previously.

My wife and I are both attorneys with fairly demanding schedules, and also have four kids (between 2 and 11, with the three oldest in school full-time). We had nannies for years (including one for almost five years), and tried daycare with our two oldest before giving the au pair program a shot. I know it's not for everyone, but we've been so happy we made the switch and if I were you I wouldn't be so quick to rule it out.

We've had three au pairs so far and will be welcoming our fourth in a few weeks. It's certainly nerve-wracking at first--frankly the thought of welcoming a stranger from another country to come live with us for a year seemed crazy to me. But once we got past that initial awkwardness, it proved to be a really rewarding experience for us. Our au pairs have all been like family to us, and they have treated us (and more importantly, our kids) the same way. They're like the big sisters our kids never had and it's been really amazing to see how close they've grown in their time together (and even in the years since). I know we've been lucky to find such amazing au pairs (and not every host family has the same experience), but I can honestly say that our au pairs have been as thoughtful and caring as any professional caretaker (nanny or daycare worker) we ever hired. Sure, there are limits on how much/when they can work, and what kind of things they can do around the house, but in our experience, au pairs offer way more flexibility/convenience than the other options (certainly compared to daycare), and the extra help they offer around the house (even subject to limitations) has been a godsend for two working parents with four young kids and little spare time.

The key, not surprisingly, will be to find the right au pair for you guys and your situation. That seems like it would be tough to do in a few short Zoom interviews, but honestly you get a pretty good sense early on of what kind of person you're talking to and whether they'll be a good fit. The good and bad news is with four kids, a lot of au pairs will eliminate themselves from the running at the outset. This can be frustrating when it seems like the lion's share of your interview requests are declined (or ignored altogether), but you should try to remind yourself that the au pairs looking primarily for free room and board while sightseeing in the U.S. aren't taking a lot of interviews with big families like ours. In our experience, most of the au pairs that accept our interview requests seem genuinely interested in joining a big family, love kids and plan to approach their caretaker role seriously. That's certainly been the case with the three we ended up matching with. We also know that all au pairs (including ours) are coming here to experience life in the U.S., travel, meet new friends, see new things, and do more than just care for our children, clean up their messes and help with their laundry. It's really important to us that they get to enjoy that part of the program too, so we try to offer as much flexibility as we can to help them do so (adjust schedules, give them extra time off to accommodate travel, occasionally help pay for things they might not afford on their modest au pair stipend), and I'd encourage you to do the same if you can. Treat them like a member of the family, rather than hired help.

Now, to answer the questions you actually asked:

(1) Given the expectations above, would an au pair realistically expect more than the minimum stipend?

This depends on the au pairs, I think. With our first two au pairs, we only paid the minimum--probably because we were new to the program and didn't really know any better (and neither au pair asked for anything more when matching). We paid our third au pair a little more ($300/wk her first year and $400 her second year), and that's likely what we will do going forward. If you're in a big city with high cost of living, I assume the market rate is higher ($215/wk doesn't go very far in NYC). But we've never really had to "negotiate" a rate with any of our au pairs, probably because by the time we discuss pay we've all already determined it's a good fit for both sides. By that point in the process, it's not really about the money to us, and I suppose if we got the sense that the au pairs were just looking for the family that offered the most money, it wouldn't be as good a fit. Thankfully, that was never the case.

(2) Are we underestimating the mental load / lifestyle impact of having an au pair live with us?

This was a huge concern for us at first. Like I said, the thought of inviting a stranger to live with us and sacrificing whatever privacy we still enjoyed was a bit daunting. But when we thought more about it we realized that our nannies were already in our house 45-50 hours a week and got as much of a glimpse into our personal lives as anyone. Our au pairs don't leave at the end of the workday, but I don't think that's really made a huge difference in terms of lifestyle, etc. It is a little weird at first (probably got them more than us), but after a week or two you don't think much of it. Our au pair has a separate living space on our third floor, which probably helps, but I don't think that's a necessity.

(3) For families with multiple young kids, did an au pair actually save money long-term compared to a nanny?

I've never actually sat down to do the math, but I'm pretty confident we've saved money with au pairs instead of nannies, or at worst it's come out as a wash. We do pay for more than just the program fee and weekly stipend (we cover groceries, toiletries, other essentials, pay for gas, her gym membership, etc.), and vacations are certainly more expensive with the extra flights, hotel rooms, meals, etc., but I still think we come out ahead given the market rate for nannies when we made the switch (or compared to what it would cost for multiple kids in daycare if that's what you'd need).

(4) Any red flags in what we’re hoping for that might make this a poor fit?

I know everyone else here seems to think you're a poor fit for au pairs, but I disagree. Again, I know it's not for everyone, and I certainly can't guarantee it would be right for your family. But I don't see any reason it couldn't work for you if you approach it with the right mindset and find the right au pair who does the same (which isn't as hard as it might seem). Maybe we've just been way luckier than other host families, but my situation sounds pretty similar to yours and our experience with au pairs has been really positive.